1. Field of the Invention
The present invention relates to a method and apparatus for determining pregnancy possibility.
2. Prior Art
Women use clinical thermometers to measure their basal body temperature each and every day, and then they can make a decision of the possibility of being pregnant on the basis of the time-sequence transition or historical record of basal body temperatures. FIG. 1 shows the time-sequence transition or historical record of the basal body temperature of women who have a twenty eight day-long menstruation period. As shown, the physical phases of the monthly body condition the woman has are closely related with the time-sequence transition or historical record of the basal body temperature. The temperature curve (a) shows the normal body condition, transferring from the low-temperature period to the high-temperature period on the ovulation day, and conversely from the high-temperature period to the low-temperature period on the ovulation day. In case of anovulation the temperature curve (b) shows little or no noticeable variation, or no temperature transition as in the normal curve (a). In case of corpus luteum insufficiency the temperature curve (c) has its high-temperature period lasting ten or less days, much shorter than the normal curve (a). As may be understood from the above, the physical phases of the monthly body condition the woman has are reflected in the time-sequence transition or historical record of the basal body temperature. As shown in FIG. 2, the basal body temperature shows a noticeable change when the woman is pregnant. Specifically the basal body temperature rises on the ovulation day, and it remains at a high-temperature level until the beginning day of the menstruation period to lower gradually if the woman is not pregnant (see broken line on curve (a) ) whereas the basal body temperature is remaining high for the menstruation period if the woman is pregnant (see solid line on curve (a) ). A decision can be made on the pregnancy possibility on the basis of such graphs.
Another method of checking the pregnancy possibility uses test papers to detect hormone if any, in urine.
As for the decision-making of pregnancy possibility relying on basal body temperature it is required that a woman holding a clinical thermometer in her mouth is lying still a few minutes in bed. This is difficult to continue a long length of time, and women often fall in sleep in bed while measuring her basal body temperature.
As for the decision-making of pregnancy possibility relying on detection of hormone in urine it is not preferable from the hygienic point of view. Throwaway test paper cannot be repeatedly used, and is rather expensive.